Expansion of optical transport networks is obtained today by increasing the network capacity and/or reach. A higher network capacity is achieved by increasing the channel rate, known as TDM (time division multiplexing) and/or increasing the density of channels in the respective transmission window, known as WDM (wavelength division multiplexing).
Advances in transmitter and receiver design, evolution of optical amplification, employment of distributed Raman amplification combined with various dispersion compensation techniques, advanced encoding and modulation techniques, digital wrapper technology, etc., enabled installation of ultra-long reach, dense WDM (DWDM) networks, where regeneration of the signal is effected at 3,000 km or more.
The next step in evolution of communications is the agile network, where the point-to-point linear/ring architecture characterized by fixed channel allocation is replaced by an agile architecture characterized by a flexible end-to-end channel allocation.
There is a need to provide a routing method, which allows automatic and flexible establishment of end-to-end routes across an agile optical network on request, so that wavelengths become resources deployable across the network. Such method should be able to provision the routes in an efficient manner to allow revenue collection based on the class of service of each individual connection.